Feather River Air Quality Management District (Yuba and Sutter Counties)www.fraqmd.org

Background

In October 2015, at the direction of the Obama Administration, U.S. EPA announced it
would move forward to implement the 2015 National Ambient Air Quality Standard
for ground-level ozone of 0.070 parts per million (ppm) averaged over 8-hours. This change
strengthened the standard by lowering it from the 2008 8-hour standard of 0.075 ppm.

The Sacramento region will remain designated as a "severe" nonattainment area for this new federal
8-hour ozone standard. The nonattainment area includes all of Sacramento and Yolo Counties, and
portions of El Dorado, Placer, Sutter and Solano Counties (see map below). It does not include
Nevada County, which has its own nonattainment area for outreach, planning and regulatory purposes.

Ground-level ozone is not emitted directly into the air, but is created by chemical reactions between
oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.
Almost 70% of the Sacramento region's ozone pollution problem comes from cars, trucks, locomotives,
buses, motorcycles, agricultural and construction equipment.

Because the Sacramento Valley is shaped like a bowl, ozone pollution presents a serious
problem in the summer when an inversion layer traps pollutants close to the ground. This lid prevents
pollutants from escaping into the upper atmosphere causing poor air quality for residents.